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Flashcards in Local Anesthesia Deck (26):
1

Which is harder to block myelinated or non-myelinated?

non-myelinated

2

Block is proximal to distal for peripheral fibers, so how does it go with core and mantle?

mantle-->core

3

Out of the alpha category which is the easiest to block?

gamma

4

Which is the easiest fiber to block overall?

B fibers

5

What are the first signs you see that a spinal/epidural anesthesia is working vs the first signs you see that a peripheral nerve block is working?

spinal/epidural
-pain-->sensory-->motor

peripheral
-first sign may be lack of proximal muscle coordination

6

What type of states of the voltage gated ion channels do local anesthetics prefer to bind?

-inactivated and open rather than resting

7

Where do local anesthetics bind?

-R site

8

What type of anesthetics can cross the membrane what type can bind the active site?

-uncharged-cross
-charged-bind

9

What determines onset time?

pH and pKa

10

What determines potency?

Lipid solubility

11

What determines duration?

protein binding
-local tissue proteins-can bind create a sink that slowly released into the nerve-more binding longer they will last

12

How can you change onset time?

raise the pH of the solution by adding sodium bicarbonate
-use a drug with a lower pKa

13

What types of drugs is the vasoconstricting power of epinephrine most useful for?

Drugs not highly protein bound like:
Lidocaine, Mepivicaine

14

What types of drugs is the vasoconstricting power of epinephrine less useful for?

Highly protein bound drugs
-ropivacaine, bupivacaine

15

What can IV lidocaine treat?

arrthymias

16

Where do you give spinal anesthesia?

L3-5 injection
-subarachnoid block
-drug deposited around cauda equina

17

What level do you give epidural?

any level
-volume dependent segmental blockade
-concentration effects blook quality
-site of action is nerve roots
-not inside dura

18

How does a blockade of thoracic level affect breathing?

-tidal volume normal
-minimal reduction in vital capacity with abdominal paralysis
-loss of proprioception can be upsetting to patient

19

If there was respiratory arrest with a high spinal block what would be the cause, what would you do?

-hypoperfusion of respiratory center in the 4th ventricle
-NEVER because of paralyzed phrenic nerves

treat with vasopressors and supportive ventilation

20

How do neuraxial anesthetics affect vascular beds?

dilation

21

What happens to the heart during neuraxial anesthesia?

brady-unopposed vagal stimulation-decreased venous return-bezold-jarisch reflex
-cardioaccelerator fibers: t1-4 blocked

22

What does absorption of the drug depend on?

-vascularity
-properties of the drug
-properties of the patient
*renal-increased blood flow-increased absorption
*more acidotic more unchanged so more easily absorbed
-additional vasoconstrictors

23

Which is more easily affected neuro or cardio?

neuro

24

WHat do you do to treat cardiac toxicity with use of local anesthetic?

intralipid
-creates a sink that LA can be sequestered into

25

What is a post dural puncture headache?

-frontal or occipital
-positional
-photophobia/ phonophobia
-may have neurological deficits

Treatment
fluid, analgesics, caffeine, blood patch

26

What causes type 1 or type 4 hypersensitivity?

esters
-paba